Collapsible foam pre-electric shave lotion containing diester lubricants

ABSTRACT

THE INVENTION RELATES TO LUBRICANT COMPOSITIONS TO FACILITATES SHAVING WITH ELECTRIC RAZORS, WHICH COMPOSITIONS CONTAIN CERTAIN DIESTER LUBRICANTS AND SURFACTANTS. METHODS OF USING THE COMPOSITIONS ARE ALSO DISCLOSED.

"United States Patent Olfice Int. Cl. A61k 1/14 US. Cl. 424-47 23 Claims ABSTRACT OF THE DISCLOSURE The invention relates to lubricant compositions to facilitate shaving with electric razors, which compositions contain certain diester lubricants and surfactants. Methods of using the compositions are also disclosed.

This application is a continuation-in-part of Application No. 297,228 filed July 24, 1963, now abandoned. The present invention is directed to lubricant compositions intended to be applied to the human skin to facilitate shaving with electric razors. Further, it relates to aerosol compositions and particularly to the production of homogeneous lubricating compositions which may be dispensed as a foam and maintained as a stable foam puff until subject to pressure, upon which the pulf collapses to a quite liquid composition.

The known preparations for lubricating the face prior to electric shaving, popularly called pre-electric shave lotions, generally comprise solutions of light esters such as isopropyl myristate or light liquid vegetable oil in essentially water-free, clear alcohol solutions. These oils may be characterized by their dry lubricity (as contrasted with mineral oil) and their insolubility in water-alcohol media. While these materials are quite suitable as lubricants, the alcohol solutions are dispensed from bottles into the hand and the thin liquids which run through the fingers are messy and wasteful to use. If the solution were to be made thicker, it would clog the razor and thus defeat the purpose of the preparation which is: (1) to dry and lubricate the face, and (2) to lubricate the razor so that it performs at top speed for easier shaving.

For a number of years a method of dispensing a desired amount of a thin alcohol containing product in a convenient easy-to-apply form has been known to the trade. This consists of formulating the product as a collapsible foam. The foam is quite stable and confined to a limited area as disperised, but readily breaks to a thin liquid when =disturbed. Such a collapsible foam formulation consists in general of approximately a 55% to 70% water-alcohol solution of the active ingredients together with 0.5% to 5.0% by weight of a surfactant which should be soluble in only one of the miscible solvents, and 3% to 15% by weight of a liquefied gas propellent which is compatible within the remaining concentrate ingredients. If a small amount of a triglyceride vegetable oil or a typical light ester (such as isopropyl myristate) is combined in such a composition, no foam is generated upon dispensing and the resultant aerosol does not lubricate sufiiciently. If more of these esters are added to the concentrate for greater lubricity, non-homogeneous three-phase systems result which are completely without foam and run through the fingers when dispensed into the hand.

The present invention provides a composition and a method to lubricate human skin and to facilitate shaving 3,824,303 Patented July 16, 1974 with electric razor when said composition is dispensed as a collapsible foam. The foam provided by the composition of the present invention is quite stable and confined to a limited area as dispensed, but readily breaks to a thin liquid when dispensed and imparts great lubricity to the skin.

The present invention is based on the discovery that the use of one or a combination of diesters of the dibasic acids which are soluble in dilute alcoholic solutions or similarly soluble diesters of polyols with monocarboxylic acids in a quick-breaking foam vehicle provides the lubricity and high concentration compatibility which is desirable in such a pre-electric shave composition. Unexpectedly, the use of these esters allowed for a stable collapsible foam to be generated when the concentrate was dispensed. In view of the oily lipophilic nature of the esters used, this stable foam is quite unusual.

In practicing the invention there is provided a composition of water and alcohol which is the major constituent and which acts as the vehicle. The composition contains a surfactant of a well-known type, described below. As the essential lubricant, there is provided either the diesters of monohydric alcohols having one to four carbon atoms with dibasic acids having 3 to 10 carbon atoms or the diesters of monobasic acids having from 2 to 8 carbons with di or polyhydric alcohols having from 3 to 8 carbon atoms, various proportions of the several constituents are adapted to carry out the desired functions. A propellent is provided which is preferably quite soluble in the composition to give the best results.

The choice of lubricant is limited only by the solubility of the ester in the particular water-alcohol vehicle chosen, its functional lubricity at suitable concentrations from a full formulation, and the property of not interfering with foam stability. Among the compounds which have been evaluated and found suitable for the purpose, either alone or in combination with other lubricants are di(isobutyl) adipate; di(n-propyl) adipate; di(isopropyl) adipate; di(methoxy polyethylene glycol [350 molecular weight]) adipate; dimethyl sebacate; 2,2,4-trimethyl 1,3 pentanediol di isobutyrate; di(methoxy ethoxy ethanol) adipate; di(methoxy ethanol) adipate; di(butoxy ethanol) phthalate; di ethyl tartrate; di(isobutyl) tartrate; di(methoxy ethanol) phthalate; propylene carbonate; triethylene glycol di(2 ethyl butyrate) and diethyl succinate, and mixtures thereof.

In general, the lower alcohol esters of the dibasic acids possess the combination of dry lubricity (similar to isopropyl myristate) together with a good water-alcohol solubility while the higher alcohol esters are more oleogenous and more water intolerant so that even an alcohol-water solution would dissolve them only with difficulty. Ester compatibility seems to vary directly with the water solubility of the alcohol used for any given dibasic acid. The larger the size of the dibasic acid the less compatible are its esters as compared to the same esters in lower molecular weight homologues. Thus, adipates are better than sebacates as far as foam stability is concerned, and isopropyl adipate is superior to isobutyl adipate.

Compounds such as isopropyl myristate, hydrogenated squalene, and dimethyl polysiloxane fluids possess an excellent lubricity when applied on the skin, but do not dissolve in alcohol-water solutions and are not suitable in the composition of the embodiment of this invention. Such high lubricating compounds may be blended, however, with other compounds described above which are very soluble in the alcohol-water system to achieve a good balance of lubricity and compatibility.

In other words, the most lubricating esters may be blended with more compatible. esters to achieve a good balance of lubricity and compatibility. The use of certain water compatible adipate esters allows for the inclusion of up to about 1.5% isopropyl myristate in a collapsible foam without undue deterioration of foam quality while permitting excellent lubricity.

The amount of diester in the formulation depends upon the nature of the diester used. The low limit is the minimum amount that will provide satisfactory lubricity and the upper limit is fixed by economic considerations, overly oily compositions, or by the amount which because of solubility and compatibility considerations will interfere with the foam stability or homogeneity of the composition at the lowest temperatures likely to be encountered in actual use. Preferably, the lower limit should not be lower than about 2.0%. The upper limit of ester concentration was reached with di(methoxy ethoxy ethanol) adipate at about 13% but perhaps even higher ester levels might be achieved. The preferred lubricant concentration is in the range of 4% to 10% with the most desirable systems.

Alcohols suitable for the compositions are usually ethyl and isopropyl alcohols. The anhydrous alcohol concentration in the over-all formula can vary from about 46% to 64% while maintaining a usable foam. The water content of the system may vary from about 34% to 21% while still maintaining a homogeneous composition at the lowest temperatures likely to be encountered in use.

The amount of surfactant employed to produce a suitable collapsible foam is not critical and for a given surfactant depends upon the ratio of water to alcohol in the formula, the quantity and nature of the diester lubricant in the formula, and to a lesser extent the pressure of the final formula. If less suitable surfactants are selected, it may be necessary to use more emulsifier to produce a satisfactory foam but under no circumstances should it be necessary to use as much as surfactant since this would minimize the lubricating effect of the preparation and ten to clog the razor. Five tenths percent to 5.0% of the surfactant blend represent the concentration extremes and 1.5% to 3.5% seems to be the preferred level to use.

The surfactant is selected from the group consisting of a mixture of polyethylene glycol esters of higher acids having 12-22 carbon atoms with polyethylene glycol ethers of higher alcohols having 12-22 carbon atoms; a mixture of polyethylene glycol esters of higher acids having 12-22 carbon atoms with higher alcohols having 16- 22 carbon atoms; a mixture of polyethylene glycol ethers of alcohols having 12-22 carbon atoms with higher alcohols having 16-22 carbon atoms; and a mixture of polyethylene glycol ethers of long chain alcohols derived from lanolin with higher alcohols having 16-22 carbon atoms.

Other surfactants which seem to be particularly suitable are conventional dimethylsilicones with a trifunctional structure, as for example, G.E. S.F. 1098 type and GE. SF. 1066 type. These surfactants are polydimethylsiloxane-polyoxyalkylene block copolymers.

The polyether portion of the molecule may contain both ethylene and propyleneloxide units, or all ethylene oxide. The average empirical formula of these compounds may be represented as follows:

GJE. SF. 1098 Type Structure 4 GE. S.F. 1066 Type Structure e 0.1 O e Ill Ia MeSi- O SIiO SIiCPh Me Me O u.1

0 l l SIiCHQCHZCHZ (i O polyether Me CH CHfl JO polyether S iCHQCHZgO polyether ll le 0 wherein a+b equals 1 and a or b may be zero and c is equal to 1, or

(The polyether moiety of the above empirical formula of GE. SF. 1066 has an average molecular Weight of 1800 and is comprised of ethylene oxide and propylene oxide in a molar ratio of 1:1).

G.E. SF. 1098 and GE. S.F. 1066 are each chemically an equilibrated carboxyalkyl containing dimethyl silicone fluid esterified with a monohydroxyl polyether.

Surfactants found to be suitable include Polawax A-3l, a trademark of Croda, Inc. which consists of a mixture of approximately 75% stearyl alcohol and 25% ethoxylated stearyl alcohol and has a molecular weight of 490.48; Promulgen, a trademark of Robinson Wagner Company, Inc. which is a non-ionic surfactant having an approximate molecular weight of 490.48 and consists of about 25 ethoxylated stearyl alcohol (20 mols ethylene oxide) and about 75 stearyl alcohol; Emulsifiable Wax No. 215, a trademark of Drew Chemical Company which consists of a mixture of 67% cetyl alcohol and 37% ethoxylated oleyl alcohol (20 mols ethylene oxide) and has a molecular weight of about 541.43; and non-proprietary blends such as the following, which are intended to be illustrative rather than limiting.

Propellents which have been used to produce homogeneous, collapsible, pre-electric shave foams include:

Propellent 22-monochlorodifiuoromethane Propellent 11trichloromonofinoromethane Propellent 12dichlorodifluoromethane Propellent 114-dichlorotetrafluoroethane Propellent 152a-difinoroethane Propellent 142b-monochlorodifluoroethane Isobutane and combinations of these in various ratios.

Gass such as Propellent 152a actually promote greater concentrate compatibility. It has been found that from 2% to 15% propellent based upon the amount of the concentrate used will produce foams, although it is preferable to use from 7% to 12% of the gas for best compati- 5. bility at lower temperatures and most complete product exhaustion from the container.

Although propellent mixtures having vapor pressures of from to 15 pounds per square inch, gauge at 70 F., can produce a usable foam, pressures of 15 p.s.i.g. or higher are preferred for best stability and generation of collapsible foams. Since the propellents used have appreciable alcohol solubility and a considerable quantity of alcohol is required in this type of product, the vapor pressure of the propellentsis reduced by the solvent effect to lower values than those stated in the literature for the pure propellent blends. For example, the gauge pressure of pure Propellent 12 at 75 F. is 77 p.s.i.g. whereas the gauge pressure of grams of the propellent in 90 grams of a concentrate containing 57% ethanol at 75 F. is 55 p.s.i.g.

The invention is more fully illustrated by the following specific examples, in which the percentages stated are by weight and are based upon the total composition including the propellent contained therein.

EXAMPLE 1 The following composition was provided:

Di(methoxy ethoxy ethanol) adipate 2.40 Denatured ethyl alcohol (95%) 68.10 Polawax A-31 4.90 Water 21.90

Isobutane 2.70

This illustrates a low propellent concentrate and the use of a hydrocarbon propellent, with satisfactory results.

EXAMPLE 2 A mixture of lubricants has been used with good results in the following formulation:

EXAMPLE 3 While myristic acid esters per se are not suitable for use in collapsible foams, it has been found that lubricant mixtures containing them in combination with certain diesters have good foam stability and may be adapted for use in the following composition:

Di(methoxy ethoxy ethanol) adipate 4.50 Denatured ethyl alcohol (95 56.10

Polawax A-31 3.60 Isopropyl myristate 0.90 Water 25.40 Difluorodichloro methane 9.50

EXAMPLE 4 In the following satisfactory composition, the lubricant is an ester of a monobasic acid:

Triethylene glycol di(2 ethyl butyrate) 3.60 Denatured ethyl alcohol (95 52.50 Polawax A-31 2.75

Water 31.65 Difiuoro ethane 9.50

EXAMPLE 5 I A somewhat different type of lubricant diester is shown in the following composition:

Propylene carbonate 3.60 Denatured ethyl alcohol (95 52.50 Polawax A-31 2.75

Water 31.65 Difluorodichloro methane 9.50

6 EXAMPLE 6 In some cases it is desirable to provide a composition which develops low pressure so that it may be used in unprotected glass bottles, of which the following formation is illustrative:

Di(isopropyl) adipate 3.05 Denatured ethyl alcohol 44.47

Polyethylene glycol (200 mol. wt.) 8.70 Polyethylene glycol (5.5 moles ETO) cetyl stearyl ether 1.85 Cetyl alcohol 1.20 Polyvinyl pyrrolidonc/vinyl alcohol copolymer 0.43 Water 27.30

Trichloromonofluoro methane 4.35 Monochlorodifiuoro ethane 8.65

It has the important advantages of exceptional low temperature, clarity and compatibility.

EXAMPLES 7 and 8 In the following examples, a different type of surfactant is used in combination with diisopropyl adipate, producing a composition which is very stable at very low temperatures.

SDA alcohol (95%) 54.00

Although the invention has been described in connection with several specific examples, the invention is not limited thereto as many variations in the details and proportions of the compositions are contemplated. For instance, other usual constituents may be added, such as perfumes, antiseptics, coloring matter, ultraviolet absorbers and the like. Other hydrocarbon and halohydrocarbons may be used in place of or in conjunction with the propellents named above. The relative proportions of the ingredients of the compositions may be varied within the above limits as, for instance, where high lubricant concentration is used which might tend to disrupt foam stability, it may be corrected by one or more of the following: introducing a more compatible lubricant, varying the relative amount of water and alcohol, increasing the amount of surfactant, or increasing the pressure.

These and other changes may be made in the details within the spirit of the invention, which is to be broadly construed and not to be limited except by the character of the claims appended hereto.

What is claimed is:

1. A method of imparting lubricity to the human skin which comprises applying thereto an effective amount of a composition from a pressure container, said composition comprising water and alcohol as the vehicle; about 0.5% to 5.0% of a surfactant selected from the group consisting of polyethylene glycol ethers of higher alcohols having 12-22 carbon atoms, a mixture of polyethylene glycol ethers of alcohols having 12-22 carbon atoms with higher alcohols having 16-22 carbon atoms, a mixture of polyethylene glycol ethers of long-chain alcohols derived from lanolin with higher alcohols having 16-22 carbon atoms, an equilibrated carboxyalkyl containing dimethyl silicone fluid esterified with a monohydroxyl polyether having the average empirical formula 2 s )12CH:, and an equilibrated carboxyalkyl containing dimethyl silicone fluid esterified with a monohydroxyl polyether and having the average empirical formula S'1O SIiO Me to a Me n b Me 0 SiiCHZCHQCHI O polyether Me O CH CHA JO polyether Me 0 S iGHZCHI O polyether Me wherein a+b equals 1, a or b may be zero, 0 equals one and the polyether moiety has an average molecular weight of 1800 and is comprised of ethylene oxide and propylene oxide in a molar ratio of 1:1; about 213% of a lubricant soluble in Water alcohol solutions selected from the group consisting of di(isobutyl) adipate, di(n-propyl) adipate, di(isopropyl) adipate, di(methoxy polyethylene glycol [350 molecular weight adipate, dimethyl sebacate, 2,2,4 trimethyl 1,3 pentanediol di-isobutyrate, di(methoxy ethoxy ethanol) adipate, di(methoxy ethanol) adipate, di(butoxy ethanol) phthalate, diethyl tartrate, di(isobutyl) tartrate, di(methoxy ethanol) phthalate, propylene carbonate, triethylene glycol di(2 ethyl butyrate), diethyl succinate, and mixtures thereof; and 2% to about of a liquefied gas propellent selected from the group consisting of halogenated hydrocarbons and saturated hydrocarbons, said saturated hydro-carbons containing 3-4 carbons.

2. The method according to Claim 1 wherein said vehicle is water and ethanol or isopropanol, and said surfactant is polyethylene glycol stearyl ether.

3. The method according to Claim 1 wherein said vehicle is water and ethanol'or isopropanol and said surfactant is an equilibrated carboxyalkyl containing dirnethyl silicone fluid esterified with a monohydroxyl polyether, and having the average empirical formula 4. The method according to Claim 1 wherein said vehicle is water and ethanol or isopropanol and said surfactant is an equilibrated carboxyalkyl containing dimethyl silicone fluid esterified with a monohydroxyl polyether, and having the average empirical formula Me SIiO Me 0.1 0 l MeSi-O- SliO |CH2 Me 0.1 Me

wherein a+b equals 1, a or b may be zero, 0 equals one and the polyether moiety has an average molecular weight of 1800 and is comprised of ethylene oxide and propylene oxide in a molar ratio of 1:1.

5. The method according to Claim 1 wherein said surfactant is a mixture of polyethylene glycol ethers of alcohols having 12-22 carbon atoms with higher alcohols having 16-22 carbon atoms.

6. The method according to Claim 1 wherein said alcohol in the vehicle is present in amount of about 46% to 64% and said water about 34% to 21% of said spray composition.

7. The method according to Claim 1 wherein said surfactant is a mixture of polyethylene glycol ethers of long chain alcohols derived from lanolin, with higher alcohols having 16-22 carbon atoms.

8. A method according to Claim 1 wherein said alcohol in the vehicle is selected from the group consisting of ethanol and isopropanol.

9. The method according to Claim 1 wherein said propellent is a chlorofiuoro hydrocarbon.

10. The method according to Claim 1 wherein said propellent is difluoroethane.

11. The method according to Claim 1 wherein said propellent is dichlorodifiuoromethane.

12. The method according to Claim 1 wherein said propellent is ethane substituted by from 2 to 6 atoms taken from the class consisting of fluorine and chlorine.

13. The method according to Claim 1 wherein said lubricant is di(isobutyl) adipate, di(n-propyl) adipate, di(isopropyl) adipate, di(methoxy polyethylene glycol [350 molecular Weight]) adipate, di(methoxy ethoxy ethanol) adipate, di(methoxy ethanol) adipate, or mixtures thereof.

14. The method according to Claim 1 wherein said lubricant is diethyl tartrate, di(isobutyl) tartrate or a mixture thereof.

15. The method according to Claim 1 wherein said lubricant is diethyl succinate.

16. The method according to Claim 1 wherein said lubricant is di(butoxyethanol) phthalate, di(methoxy ethanol) phthalate or a mixture thereof.

17. The method according to Claim 1 wherein said lubricant is propylene carbonate.

18. The method according to Claim 1 wherein said lubricant is triethylene glycol di(2 ethyl butyrate).

19. The method according to Claim 1 wherein said lubricant is dimethyl sebacate.

20. The method according to Claim 1 wherein said lubricant is 2,2,4 trimethyl 1,3 pentanediol di-isobutyrate.

and an equilibrated carboxyalkyl containing dimethyl silicone fluid esterified with a monohydroxyl polyether and having the average empirical formula Itfle I e (S|i 510 Me to 0/ 0.1

| Me Me I. l. I. MeSr- MeS1O- 5'10 Sl1CH2 0.1 Me i 0 e to n SiO - I II SIiCHzCHzCHZCO polyether Me CHzCHaHlO polyether lltle s icmcmi zo polyether wherein a+b equals 1, a or b may be zero, 0 equals one and the polyether moiety has an average molecular weight of 1800 and is comprised of ethylene oxide and propylene oxide in a molar ratio of 1:1; about 2-13% of a lubricant soluble in water alcohol solutions selected from the group consisting of di(isobutyl) adipate, di(n-propyl) adipate, di(isopropyl) adipate, di(methoxy polyethylene glycol [350 molecular weight]) adipate, dimethyl sebacate, 2,2,4 trimethyl 1,3 pentanediol di-isobutyrate, di(methoxy ethoxy ethanol) adipate, di(methoxy ethanol) adipate, di(butoxy ethanol) phthalate, diethyl tartrate, di(isobutyl) tartrate, di(methoxy ethanol) phthalate, propylene carbonate, triethylene glycol di(2 ethyl butyrate), diethyl succinate, and mixtures thereof; and 2% to about 15% of a liquefied gas propellent selected from the group consisting of halogenated hydrocarbons and saturated hydrocarbons, said saturated hydrocarbons containing 3-4 carbons.

22. The composition according to Claim 21 in which said alcohol in the vehicle is present in amount of about 46% to 64% and said water about 34% to 21% of said composition.

23. The composition according to Claim 21 in which said surfactant is a mixture of polyethylene glycol ethers of higher alcohols having 12-22 carbon atoms with higher alcohols having 16-22 carbon atoms.

References Cited UNITED STATES PATENTS 2,268,347 12/ 1941 Steinberg 424-313 2,273,860 2/ 1942 Granett 424-313 3,072,535 1/1963 Mueller 42473 3,190,802 6/ 1965 Zeile et al 424--73 3,298,919 1/ 1967 Bishop et al. 42473 JEROME D. GOLDBERG, Primary Examiner V. C. CLARKE, Assistant Examiner U.S. Cl. X.R. 

